Chimeric proteins and methods of immunotherapy

Abstract

The present disclosure provides systems for immune cell regulation and methods of immunotherapy. Systems of the present disclosure for immune cell regulation comprise a chimeric receptor polypeptide, a chimeric adaptor polypeptide, a gene modulating polypeptide (GMP), and a cleavage moiety.

What is claimed is: 
     
       1. A method of inducing death of a target cell, comprising:
 (a) expressing a system in a lymphocyte; and 
 (b) contacting said target cell with the lymphocyte under conditions that induce said death of the target cell, 
 wherein the system expressed in the lymphocyte comprises:
 (i) a chimeric transmembrane receptor polypeptide (receptor) comprising a ligand binding domain, an immune cell signaling domain, and a gene modulating polypeptide (GMP), wherein the GMP comprises an actuator moiety linked to a cleavage recognition site, wherein the actuator moiety modulates expression and/or activity of an immune regulatory protein of the lymphocyte, and wherein the immune regulatory protein enhances lymphocyte cytotoxicity and/or reduces a side effect of lymphocyte activation; and 
 (ii) a chimeric adaptor polypeptide (adaptor) comprising a receptor binding moiety linked to a cleavage moiety, wherein the cleavage moiety is capable of cleaving the cleavage recognition site on the receptor when the receptor binding moiety of the adaptor binds the immune cell signaling domain of the receptor in response to binding of the ligand binding domain of the receptor to a ligand present on the target cell, and wherein the adaptor does not bind a ligand present on the target cell; 
 
 wherein the receptor is activatable upon binding to the ligand present on the target cell to recruit the adaptor to the receptor in the lymphocyte, and wherein the recruited adaptor releases the actuator moiety from the GMP of the receptor by action of the cleavage moiety at the cleavage site, thereby inducing death of the target cell. 
 
     
     
       2. The method of  claim 1 , wherein modulation of expression and/or activity of the immune regulatory protein enhances cytotoxicity of the lymphocyte compared to a system in which the immune regulatory protein expression and/or activity is not modulated. 
     
     
       3. The method of  claim 1 , wherein modulation of expression and/or activity of the immune regulatory protein reduces a side effect of lymphocyte activation compared to a system in which the immune regulatory protein expression and/or activity is not modulated, wherein the side effect is hypercytokinemia. 
     
     
       4. The method of  claim 1 , wherein the actuator moiety up-regulates expression and/or activity of the immune regulatory protein. 
     
     
       5. The method of  claim 1 , wherein the actuator moiety down-regulates expression and/or activity of the immune regulatory protein. 
     
     
       6. The method of  claim 1 , wherein the immune regulatory protein is selected from A2AR, B7.1, B7-H3/CD276, B7-H4/B7SI/B7x/Vtcn1, B7-H6, BTLA/CD272, CCR4, CD122, 4-1BB/CD137, CD27, CD28, CD40, CD47, CD70, CISH, CTLA-4/CD152, DR3, GITR, ICOS/CD278, IDO, KIR, LAG-3, OX40/CD134, PD-1/CD279, PD2, PD-L1, PD-L2, TIM-3, and VISTA/Dies1/Gi24/PD-1H (C10orf54). 
     
     
       7. The method of  claim 6 , wherein the immune regulatory protein is PD-1 or CTLA-4. 
     
     
       8. The method of  claim 1 , wherein the immune regulatory protein is an immune checkpoint receptor. 
     
     
       9. The method of  claim 1 , wherein the target cell is a cancer cell. 
     
     
       10. The method of  claim 9 , wherein the cancer cell is of hematopoietic lineage or a B-cell lymphoma cell. 
     
     
       11. The method of  claim 9 , wherein the lymphocyte exhibits an enhanced ability to induce death of the target cell as compared to that of a control lymphocyte, wherein the enhanced ability to induce death of the target cell is at least a 1.5-fold increase in induced cell death. 
     
     
       12. The method of  claim 9 , wherein the cancer cell expresses a ligand indicative of a B-cell lymphoma. 
     
     
       13. The method of  claim 1 , wherein the ligand is CD19. 
     
     
       14. The method of  claim 1 , wherein upon binding of the ligand binding domain to the ligand, the receptor undergoes a receptor modification comprising phosphorylation. 
     
     
       15. The method of  claim 14 , wherein the receptor modification comprises phosphorylation at multiple modification sites, and wherein each modification site is effective to bind a chimeric adaptor polypeptide. 
     
     
       16. The method of  claim 1 , wherein the enhanced lymphocyte cytotoxicity is evidenced by a reduced size of tumor comprising the target cell.